1. Field of the Invention
The subject invention relates to a compressor assembly for a climate control system of a vehicle, and more specifically to a variable displacement compressor assembly.
2. Description of the Prior Art
U.S. Pat. No. 4,606,705, issued to Parekh, discloses a variable angle wobble plate compressor assembly used in vehicle air conditioning systems. The compressor assembly of the '705 patent includes a compressor housing defining a suction cavity for receiving a fluid (refrigerant) at a suction pressure, a discharge cavity for receiving the fluid from the suction cavity at a discharge pressure higher than the suction pressure, and a crankcase in fluid communication with the discharge cavity. The crankcase encloses a variable angle wobble plate and at least one compressor piston having a variable piston stroke therein. A control valve for controlling a fluid pressure within the crankcase is disposed in the compressor housing. The control valve includes a valve casing defining a chamber therein. The valve casing includes a suction port in fluid communication with the suction cavity for providing the fluid at the suction pressure from the suction cavity to the chamber. A bellows is moveable in the chamber between an activated position and a neutral position. The member is responsive to the fluid at the suction pressure and is urged into the activated position when the suction pressure is below a pre-determined set-point. The activated position opens fluid communication between the discharge cavity and the crankcase while closing fluid communication between the suction cavity and the crankcase. The activated position is for pressurizing the crankcase with the fluid at the discharge pressure to decrease the angle of the wobble plate and thereby the piston stroke. The neutral position closes fluid communication between the discharge cavity and the crankcase while opening fluid communication between the suction cavity and the crankcase. The neutral position is for pressurizing the crankcase with the fluid at the suction pressure to increase the angle of the wobble plate, and thereby the piston stroke, so that the compressor assembly operates at maximum capacity. A solenoid is connected to the member and responsive to an electric signal for actuating the member into the activated position when the suction pressure is above the pre-determined set-point.
Accordingly, the solenoid must be capable of providing a sufficient force to mechanically move the member into the activated position to allow the fluid at the discharge pressure to flow into the crankcase to de-stroke the compressor.